Galvanizing flux



sheet-iron exhibits lustre.

Patented Nov. 10, 1925. t

, UNITED, s rrts PATENT OFFICE.

UMEJIRO EMURA, OF TOKYO, JAPAN, ASSIGNOR TO 'IEIJI YAMANOUCHI, OF TOKYO,

' JAPAN.

GALVANIZING FLUX.

No Drawing.

To'all whom it may concern:

Be it known that UMnJmo EMURA, a sub ject of the Emperor of Japan, residing at N o. 99 Kaminakasato, Takinogawa, Kltatoshima-gori, Tokyo Prefecture, Japan, has invented certain new and'useful Improvements in Galvanizing Flux, of which the following is a specification.

This invention relates to improvements in the manufacture of galvanized sheet-iron in which proper quantities ofthe following sorts of substances, i. e., metallic strontium or strontium compounds, sulphur, carbonates or sulphur compounds, chlorides, and metallic bismuth or bismuth compounds are previously added to ammonium chloride which has been hitherto used to protect molten zinc from oxidation. The objects of this invention are to give greater brightness to galvanized sheet-iron as well as to increase its resistance to oxidation.

According to my experiments the galvanized sheet-iron does not show any im roved brightness when it is manufactured y immersing sheet-iron in molten zinc covered with molten ammonium chloride, the hitherto used oxidation preventing agent, mixed with" only metallic strontium or. its compounds, for instance, strontium carbonate. The strontium bearing compound and ammonium chloride, .even after the addition of sulphur, does not improve the brightness of the surface of the galvanized sheet, when 'ap lied thereto. But when ,proper quanllltlGSOf a chloride such as sodium chloride or potassium chloride and a sulphur compound such as sodium sulphide or potassium sulphide, or a carbonate such as sodium carbonate or potassium carbonate which forms a sulphide with the sulphur previously mixed, are added, the surface of galvanized When the sheetiron is galvanized after addition of metallic bismuth or its compounds such as basic bismuth carbonate, bismuth nitrite or bismuth sulphide to the flux, the surface is found to show fine lustre and strong brightness which are lackin in the above cases. The func-. tion of eac substance for the a pearance of lustre and brightness is not c ear but the formation of complex compounds produced by the mutual action of the sulphide such as strontium sulphide, bismuth sulphide, sodium sulphide or potassium sulphide and the chloride such as sodium chloride or potas- Application filed May 26, 1922. Serial No. 563,964.

sium chloride, and especially the existence of bismuth sulphide are thought to be the main factors. I

In carrying out these experiments technically on a larger scale, the mixture of the following proportion by weight is used.

Sulphur compounds or carbonates 10- 2O Metallic bismuth or its compounds 20- 30 Chlorides 3- 5 Further details are shownin the following examples Ex. 1. Metallic strontium 73. Sulphur, ure 48. Metallic bismuth 18. Sodium carbonate 13. Sodium chloride...; 5.

Ex. 2. Strontium chloride 100. Sodium sul hide 10. Bismuth sulphideu u; 20. Sodium chloride 5.

Ex.3. Strontium carbonate 124.

' Sul 'hur, pure 62. Basic bismuth carbonate 22. Sodium carbonate 13. Sodium chloride 5.

Ext. Strontium carbonate 124. Sulphur, pure 62.. Bismuth nitrite 25. Sodium carbonate 13. Sodium chloride 5.

Since bismuth nitrite is cheapest of the bismuth containing materials, the mixture with the proportion mentioned in Example 4 is hi hly economical and of practical use.

In t e manufacture of galvanized sheetiron, 2-3% of the above mixture is added to ammonium chloride which has been hitherto used to protect molten zinc from oxidation. 'In practice, the mixture covers the surface of molten zinc 2-3 inches thick; When the mutual action in the mixture is completed by the heat of molten zinc, sheet- .iron is immersed in the bath.

When ammonium chloride alone is used as hitherto, molten zinc is protected from oxidation during the o oration. The surface of the finished ga vanized sheet-iron, however, assumes white color after 2-3 weeks owing to the oxidation by air. But

according to the-:present method, the finished sheet-iron is covered by certain mixtures which keep the product permanently in bright and lustrous state, thus enablin the manufacturer to furnish improved ga vanized sheet-iron.

I claim-- sul hur, a bismuth bearing material, and alkali metal'compounds, substantiallyas set forth.

' 2. A galvanizing flux comprising a large proport on of ammonium chloride mixed with afew per cent of its weight of strontium-containin and bismuth-containing materials, an alka metal chloride and sulfur.

3. A galvanizing flux containing ammonium chlorid mixed with about 2 to 3% of its weight of a mixture containing strontium carbonate, about 124 parts sulfur, about 62.5 parts; bismuth nitrite, about 25.6 parts; sodium carbonate, about 13.6 parts; sodium chloride, about 5 parts.

ture.

UMEJIRO EMURA.

In testimony whereof he aflixes his signa- 

